LI20.10-P-060902

Engine diagnosis warning lamp activated - Fault code P012800
Topic number
LI20.10-P-060902
Version
7
Function group
20.10 Coolant pump, coolant thermostat
Date
08-03-2020
Validity
Engine 270 and engine 274
Reason for change
Reference to Service Information added
Reason for block
Complaint:
Engine diagnosis warning lamp activated - The fault code P012800 "The coolant temperature is below the coolant
thermostat specified temperature" is stored in the engine control unit.
Cause:
After engine start, the engine coolant warms up more slowly than specified in the curve stored in the engine control
unit.
Remedy:
NOTE: For all vehicles, check the engine control unit for a software update and update this if necessary.
REMEDY:
- Perform guided test "Check component R48 (coolant thermostat heating element)" and process according to the
XENTRY instructions.
- Observe SI20.10-P-0005A if thermostat replacement is required. Remove filter screen on new thermostat if installed.
NOTE: Whenever work is performed to the cooling system, it is always necessary to refill the system with new coolant.
- When the work is complete, warm up the vehicle completely, erase the fault memory, leave the vehicle to cool down
(at least 8 hours) and then perform a test drive; a coolant temperature of at least 70 °C must be reached during the
test drive.
Symptoms
Power generation / Engine cooling system / Function / Does not reach operating temperature
Body / Air conditioning / Heater / Insufficient heat output
Power generation / Engine management / Indicator lamp / Engine diagnosis / lit
Control unit/fault code
Control unit
08-03-2020 3:23 PM
© Copyright Mercedes-Benz AG
Fault code
Fault text
CBUTCHE
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N3/10 - Motor electronics
'MED40' for combustion engine 'M274' (ME)
P012800
The coolant temperature is below the coolant thermostat specified temperature. _
N3/10 - Motor electronics 'ME- P012800
D40CNG' for combustion engine 'M274' (ME) (B (242, 246),
E (212))
The coolant temperature is below the coolant thermostat specified temperature. _
Operation numbers/damage codes
Op. no.
Operation text
Time
Damage
code
Note
54-1011
PERFORM QUICK TEST
54575 90
54-0991
PROGRAM CONTROL UNIT (AFTER
QUICK TEST)
54575 90
As required, if necessary
20-2470
REMOVE/INSTALL
COOLANT THERMOSTAT, REPLACE
IF NECESSARY
20103 73
As required, if necessary
54-0650
ON-BOARD POWER SUPPLY VOLTAGE MAINTAIN
WIS-References
Document number
Title
Note
SI20.10-P-0005A
Service Information: Coolant
thermostat with filter screen
Allocation
Remedy
Validity
Vehicle
Engine
Transmission
*
274
*
*
270
*
08-03-2020 3:23 PM
© Copyright Mercedes-Benz AG
CBUTCHE
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